Clunking drive Line on pushing or releasing accelerator

[John_Mc]

Driving me crazy. Every time I either hit the gas or back off the drive line gives a loud clunk. It started as a clunk when selecting between drive and reverse. If I grab the drive shafts and rotate them it will turn aprox 1/8 of a turn. The rear diff sounds a bit noisy at speed. Took it to an auto/diff place in Townsville, as I was travelling away from home in Sydney, and was told the front and rear diffs at fault and probably also the transfer case chain. I had the rear diff overhauled and they found overheated main bearings, they lapped and shimmed the pinion etc and $1800 later still same and diff still noisy but no free play in rear drive shaft still free play in front. If I put it in H4 with Ctr diff lock noise is much much less. Anyone had similar problem? P.S. I have been towing a 3000 kg caravan for the last 2 years and done aprox 30,000 towing in H4. Noise got much worse just after rear diff bushes changed to polly bushes. During rear diff bushes change I had them undo and re-torque the rear hub nuts, which were tight and ceases. After the rear diff rebuild there is a clunk every time I brake heavy, ok if braking gentle.

[twisted32]

Driving me crazy. Every time I either hit the gas or back off the drive line gives a loud clunk. It started as a clunk when selecting between drive and reverse. If I grab the drive shafts and rotate them it will turn aprox 1/8 of a turn. The rear diff sounds a bit noisy at speed. Took it to an auto/diff place in Townsville, as I was travelling away from home in Sydney, and was told the front and rear diffs at fault and probably also the transfer case chain. I had the rear diff overhauled and they found overheated main bearings, they lapped and shimmed the pinion etc and $1800 later still same and diff still noisy but no free play in rear drive shaft still free play in front. If I put it in H4 with Ctr diff lock noise is much much less. Anyone had similar problem? P.S. I have been towing a 3000 kg caravan for the last 2 years and done aprox 30,000 towing in H4. Noise got much worse just after rear diff bushes changed to polly bushes. During rear diff bushes change I had them undo and re-torque the rear hub nuts, which were tight and ceases. After the rear diff rebuild there is a clunk every time I brake heavy, ok if braking gentle.

Rear diff poly bushes will be the main contributing factor. Factory rubber masks the issue as it is part of the inherent design.
I have poly bushes and the clunk is much more evident on light throttle gear changes, with the torque converter locked.
You may have some backlash, but I doubt it is a problem.
If you don't like the stability poly diff bushes give, go back to factory rubber

[John_Mc]

Thanks twisted32 for the reply. I just cant believe it would make such a big change putting polly bushes in but have heard others complain about them.

[John_Mc]

After months of inquires to many gear box repairers, I now believe the transfer case chain has worn and has massive backlash as well as both diffs.

[geopaj]

After months of inquires to many gear box repairers, I now believe the transfer case chain has worn and has massive backlash as well as both diffs.

How many kms has it done total?

I’ve not heard s occurring before.

[psproule]

The chains do stretch. When really bad they jump teeth in the tough stuff when in 4LLc.

Pat

[Ian H]

I had a loud clunk in mine which turned out to be as simple as a loose stub axle. A good heave on a long spanner and she was all good again.

[NT11Pajero]

Sounds like I've got a similar issue. It's annoying as I can hear it every time I touch the accelerator! Will investigate bushes and tighten bolts and see if that helps